1. Field of the Invention
The present invention relates to a cannula assembly used in insufflatory surgery. In one aspect, the invention relates to a cannula cap for sealing a cannula assembly while in another aspect, the invention relates to a adaptor cap for use in combination with the cannula cap.
2. Background of the Invention
Various types of cannula assemblies have been provided with valves for maintaining a certain gas pressure in a body cavity during insufflatory surgery. Insufflatory surgery involves filling a body cavity with pressurized gas to maintain the cavity under a certain predetermined pressure. A conventional technique of performing the surgery is to first puncture the skin in a predetermined region of the body cavity with a needle including a stylet, and introducing an insufflatory gas into the body cavity. Once pressurized, one or more cannula assemblies are inserted into the body cavity at predetermined locations (other than that at which the insufflatory gas is introduced).
A trocar is inserted into the bore of the cannula with its sharpened end extending from the distal end of the cannula. The sharpened end of the trocar is used to enable the distal end of the cannula to enter the body cavity. The trocar is then removed from the cannula, and surgical instruments inserted through the cannula to perform required endoscopic procedures. Because the body cavity is under pressure, escape of the insufflatory gas must be prevented during insertion of the instruments and the performance of the surgical procedure.
The art teaches various types of cannula assemblies provided with valves for maintaining gas pressure in the body cavity when the trocar or other surgical instruments are inserted and removed from the cannula.
U.S. Pat. No. 4,177,814 discloses a self-sealing cannula which maintains insufflation pressure in a body cavity by means of a slotted elastomeric valve positioned in a valve seat with the slot disposed over the cannula valve passage. Separate means are provided to compress the valve against a valve seat to seal the slot or slots.
U.S. Pat. No. 3,853,127 discloses a certain type of perforation formed in an elastic sealing member.
U.S. Pat. No. 3,994,287 discloses an assembly wherein gas pressure is maintained by means of a flexible ring having an aperture positioned within an annular valve seat. A collar is placed over the ring to seal the sidewalls of the valve seat. Since the disclosed assembly loses it seal when the surgeon removes the instrument, other sealing means must be provided to maintain gas pressure.
U.S. Pat. No. 3,989,049 discloses a trumpet valve to maintain pressure. The valve must be manually regulated by the surgeon while removing the trocar and replacing it with another instrument, such as a laparoscope.
U.S. Pat. No. 5,041,095 discloses a hemostasis valve to prevent blood leakage. This valve assembly utilizes a snap-on cap which houses at least a pair of separate discs, each having slots for receiving a catheter to prevent backflow of blood.
U.S. Pat. No. 5,092,846 discloses a device for introducing a catheter into a body for diagnosis or treatment, as in the case of a vascular balloon catheter.
U.S. Pat. No. 5,104,383 discloses a seal for use with a cannula assembly. This disclosure is directed principally to a stabilizer plate to limit the eccentric movement of an instrument relative to the seal which might otherwise inadvertently break the seal.
U.S. Pat. No. 5,114,408 discloses a hemostasis valve formed of a longitudinally extended valve housing. An apertured cap is provided for enclosing a first opening of the housing. The cap permits insertion of a catheter.
U.S. Pat. No. 5,122,122 discloses a trocar sleeve provided in a relatively complicated assembly requiring an expanded end of the trocar sleeve in abutting relationship with the inner surface of the abdominal cavity.
Patent Publication 0 334 907 A2 discloses a particular configuration of slits formed in a self-sealing gasket for a catheter.